Vehicle tire shreds can be reduced through anaerobic pyrolysis to produce solid pyrolysate in the form of carbon black and fluid pyrolysate in the form of valuable hydrocarbon liquids and gases.
Prior tire-shred pyrolysis systems have operated on a batch basis, that is, one "batch" of tire shreds is pyrolyzed at a time with intervening steps in which no pyrolysis takes place. The main component of a batch pyrolysis system is a pyrolysis chamber with at least one sealable opening through which tire shreds are fed into the chamber and solid pyrolysate is removed. The prior pyrolysis systems also include heating means for heating the tire shreds in the sealed pyrolysis chamber to a pyrolyzing temperature, and a purging system to purge the sealed pyrolysis chamber of air prior to heating each batch.
According to the batch pyrolyzing process, tire shreds are first loaded into the pyrolyzing chamber and the chamber is then sealed. The entire chamber is next purged of air to remove oxygen which would otherwise react with the hydrocarbon gases and liquids liberated during pyrolysis. The contents of the chamber are then heated to a pyrolyzing temperature for a sufficient period of time to pyrolyze the enclosed tire shreds. After the period of heating time required for complete pyrolysis of the enclosed tire shreds, the chamber is opened, the solid pyrolysate is removed, and the chamber is cleaned in preparation for the next batch.
The prior pyrolysis systems have proven inadequate for several reasons. First, the prior systems were very laborintensive since the chamber had to be manually loaded, sealed, opened, and then cleaned for each batch. The prior systems were also wasteful in that valuable gas and liquid pyrolysate was not recovered. Prior systems also released pyrolysate gas into the atmosphere, which was not only wasteful, but also harmful to the environment. Furthermore, since the entire chamber and its contents had to be reheated for each tire-shred batch, the prior systems made very inefficient use of heating energy.
It is therefore an object of the invention to provide a continuous tire-shred pyrolysis system in which tire-shred input, pyrolysate output, and pyrolysis all occur simultaneously.
Another object of the invention is to provide a continuous tire-shred pyrolysis system that recovers solid, liquid, and gas pyrolysate.
A further object of the invention is to provide a tire-shred pyrolyzing system that makes efficient use of pyrolyzing energy.